Spectrum 9.3.x upgrade to Spectrum 10.1 now supported

SUMMARY: We have a lot of customers still on Spectrum 9.3.x and to facilitate and motivate people to get to Spectrum 10.x easily, we conducted tests and now officially support upgrading from directly from Spectrum 9.3.x to Spectrum 10.1. It is a single hop upgrade now - no need to go to 9.4 or 10.0 before installing Spectrum 10.1